The inborn errors of metabolism that are currently under investigation are hyperlysinemia, Lesch-Nyhan disease, maple syrup urine diseas and isvaleric acidemia. In alinstance, studies are being conducted on the skin fibroblast growing in tissue culture. The effect of pederine in producing in vitro cell fusion is also under investigation. Shin biopsies and blood samples (for lymphocyte culture) are obtained from the patients.